The world is becoming digital. Digital signals are everywhere--in our computers, television sets, VCRs, home stereos, and CD players. Digital processing--which operates on information "bits" (numerical "on" or "off" values)--provides a degree of precision and protection from noise that cannot be matched by the older, "analog" formats we have used since the beginning of the electronic age.
Despite the clear advantage of digital communications, the older "analog" domain remains significant. Many of our most important information delivery mechanisms continue to be based on analog--not digital--signaling. In fact, most of our electronic entertainment, news, sports and music program material comes to us in the form of analog signals. For example:
Television remains largely analog. Although the distribution of television programming to local cable systems is increasingly digital and most modern television sets include digital signal processing circuits, the local cable television "head end" continues to send television signals to the subscriber's set top box and television in analog--not digital--form. It will cost a great deal to convert local cable distribution from analog to digital. In the United States, for example, the widespread conversion from analog to digital television is projected to take no less than 15 years and perhaps even longer. PA1 In radio broadcasting, too, analog communication continues to reign supreme. Thousands of radio stations broadcast music, news and other programs every day in analog form. Except for a few experimental digital systems, practically all radio broadcasting is carried over analog communications channels. PA1 The movies and videos we rent at the local video tape rental store are analog. PA1 Commercially available music tape cassettes are recorded in analog formats. PA1 Quality degradation inherent in multigenerational analog copying has not prevented a multi-billion dollar pirating industry from flourishing. PA1 Some methods for video tape copy and pay per view protection attempt to prevent any copying at all of commercially released content, or allow only one generation of copying. These methods can generally be easily circumvented. PA1 Not all existing devices respond appropriately to copy protection signals. PA1 Existing schemes are limited for example to "copy/no copy" controls. PA1 Copy protection for sound recordings has not been commercially implemented. PA1 An indelible and invisible, secure technique for providing rights management information. PA1 An indelible method of associating electronic commerce and/or rights management controls with analog content such as film, video, and sound recordings. PA1 Persistent association of the commerce and/or rights management controls with content from one end of a distribution system to the other--regardless of the number and types of transformations between signaling formats (for example, analog to digital, and digital to analog). PA1 The ability to specify "no copy/one copy/many copies" rights management rules, and also more complex rights and transaction pricing models (such as, for example, "pay per view" and others). PA1 The ability to fully and seamlessly integrate with comprehensive, general electronic rights management solutions (such as those disclosed in the Ginter et al. patent specification referenced above). PA1 Secure control information delivery in conjunction with authorized analog and other non-digital and/or non-secure information signal delivery mechanisms. PA1 The ability to provide more complex and/or more flexible commerce and/or rights management rules as content moves from the analog to the digital realm and back. PA1 The flexible ability to communicate commerce and/or rights management rules implementing new, updated, or additional business models to authorized analog and/or digital devices. PA1 In ancient Persia an important message was once tattooed on a trusted messenger's shaved scalp. The messenger then allowed his hair to grow back--completely hiding the message. Once the messenger made his way to his destination, he shaved his hair off again--exposing the secret message so the recipient could read it on the messenger's shaved scalp. See Kahn, David, The Codebreakers page 81 et seq. and page 513 et seq. (Macmillan 1967). This unusual technique for hiding a message is one illustration of"steganography." PA1 Another "steganographic" technique encodes a secret message within another, routine message. For example, the message "Hey Elmer, Lisa Parked My Edsel" encodes the secret message "HELP ME"--the first letter of each word of the message forming the letters of the secret message ("Hey Elmer, Lisa Parked My Edsel"). Variations on this technique can provide additional security, but the basic concept is the same--finding a way to hide a secret message within information that can or will be sent over an insecure channel.
Moreover, the "real world" is analog. Everything digital must ultimately be turned into something analog if we are to experience it; and conversely, everything analog must be turned into something digital if the power of modern digital technology will be used to handle it. Modern digital technology also allows people to get better quality for less money.
Despite the pervasiveness of analog signals, existing methods for managing rights and protecting copyright in the analog realm are primitive or non-existent. For example:
A related problem relates to the conversion of information between the analog and digital domains. Even if information is effectively protected and controlled initially using strong digital rights management techniques, an analog copy of the same information may no longer be securely protected.
For example, it is generally possible for someone to make an analog recording of program material initially delivered in digital form. Some analog recordings based on digital originals are of quite good quality. For example, a Digital Versatile Disk ("DVD") player may convert a movie from digital to analog format and provide the analog signal to a high quality analog home VCR. The home VCR records the analog signal. A consumer now has a high quality analog copy of the original digital property. A person could re-record the analog signal on a DVD-R (a Digital Versatile Disk appliance and media supporting both read and write operations). This recording will in many circumstances have substantial quality--and would no longer be subject to "pay per view" or other digital rights management controls associated with the digital form of the same content.
Since analog formats will be with us for a long time to come, rightsholders such as film studios, video rental and distribution companies, music studios and distributors, and other value chain participants would very much like to have significantly better rights management capabilities for analog film, video, sound recordings and other content. Solving this problem generally requires a way to securely associate rights management information with the content being protected.
People have for many years been using various techniques allowing digital information to, in effect, ride "piggyback" on analog information signals. For example, since the 1960s, it has been common to digitally encode text information such as subtitles into otherwise unused portions of analog television signals (e.g., within the so-called "Vertical Blanking Interval").
Unfortunately, sending digital information using such known digital encoding techniques is problematic because the digital information is not persistent. It is relatively easy to strip out or eliminate digital information encoded using prior techniques commonly employed for superimposing digital signals onto an analog information signal. Analog communications channels may commonly be subjected to various signal processing that may (intentionally or unintentionally) strip out digital information added to the analog signal--defeating any downstream system, process or technique that depends on the presence and readability of the digital information. For example, the television vertical blanking signal--along with any signal components disposed within the vertical blanking interval--is typically routinely eliminated whenever a video signal is processed by a computer.
Attempting to use insecure techniques for providing rights management is at best ineffective, and can be worse than no rights management at all. Unscrupulous people can strip out insecure control information altogether so that the corresponding information signal is subject to no controls at all--for example, defeating copy protection mechanisms and allowing users to avoid paying for rights usage. More nefariously, an unscrupulous person could alter an insecure system by substituting false control information in place of the proper information. Such substitutions could, for example, divert payments to someone other than legitimate rights holders--facilitating electronic fraud and theft.
Prior, insecure techniques fail to solve the overall problem of how to provide and securely manage advanced automatic electronic rights management for analog and other information signals conveyed over an insecure communications channel. The lack of strong rights management for analog signals creates a huge gap in any comprehensive electronic rights management strategy, and makes it possible for consumers and others to circumvent--to at least some extent--even the strongest digital rights management technologies. Consequently, there is a real need to seamlessly integrate analog delivery models with modern electronic digital rights management techniques.
The present inventions solve these and other problems by providing "end to end" secure rights management protection allowing content providers and rights holders to be sure their content will be adequately protected--irrespective of the types of devices, signaling formats and nature of signal processing within the content distribution chain. This "end to end" protection also allows authorized analog appliances to be easily, seamlessly and cost-effectively integrated into a modern digital rights management architecture.
The present inventions may provide a Virtual Distribution Environment ("VDE") in which electronic rights management control information may be delivered over insecure (e.g., analog) communications channels. This Virtual Distribution Environment is highly flexible and convenient, accommodating existing and new business models while also providing an unprecedented degree of flexibility in facilitating ad hoc creation of new arrangements and relationships between electronic commerce and value chain participants--regardless of whether content is distributed in digital and/or analog formats.
The present inventions additionally provide the following important and advantageous features:
Briefly, the present inventions use "steganography" to substantially indelibly and substantially invisibly encode rights management and/or electronic commerce rules and controls within an information signal such as, for example, an analog signal or a digitized (for example, sampled) version of an analog signal.
The Greek term "steganography" refers to various "hidden writing" secret communication techniques that allow important messages to be securely carried over insecure communications channels. Here are some examples of steganography:
Invisible ink is another commonly used "steganography" technique. The secret message is written using a special disappearing or invisible ink. The message can be written on a blank piece of paper, or more commonly, on the back or front of the piece of paper carrying a routine-looking or legitimate letter or other written communication. The recipient performs a special process on the received document (e.g., exposing it to a chemical or other process that makes the invisible ink visible) so that he or she can read the message. Anyone intercepting the paper will be unable to detect the secret message--or even know that it is there--unless the interceptor knows to look for the invisible message and also knows how to treat the paper to make the invisible ink visible
The present inventions use steganography to ensure that encoded control information is both substantially invisible and substantially indelible as it passes over an insecure communications channel. At the receiving end, a secure, trusted component (such as a protected processing environment described in Ginter et al.) recovers the steganographically-encoded control information, and uses the recovered information to perform electronic rights management (for example, on analog or other information signals carried over the same channel).
One specific aspect provided by the present inventions involve steganographically encoding digital rights management control information onto an information signal such as, for example, an analog or digitized television, video or radio signal. The steganographic encoding process substantially inextricably intertwines the digital control information with images, sounds and/or other content the information signal carries--but preferably without noticeably degrading or otherwise affecting those images, sounds and/or other content. It may be difficult to detect (even with educated signal processing techniques) that the analog signal has been steganographically encoded with a rights management control signal, and it may be difficult to eliminate the steganographically encoded control signal without destroying or degrading the other information or content the signal carries.
The present inventions also provide a secure, trusted protected processing environment to recover the steganographically-encoded control signal from the information signal, and to enforce rights management processes based on the recovered steganographically encoded control signal. This allows the information signal delivery mechanism to be fully integrated (and made compatible) with a digital virtual distribution environment and/or other electronic rights management system.
In accordance with yet another aspect provided by this invention, steganographically encoded, digital rights management control information may be used in conjunction with a scrambled and/or encrypted information signal. The scrambling and/or encryption can be used to enforce the rights management provided in accordance with the steganographically encoded rights management control information. For example, the control signal can be steganographically decoded and used to control, at least in part, under what circumstances and/or how the information signal is to be descrambled and/or decrypted.
In accordance with yet another feature provided by the invention, digital certificates can be used to securely enforce steganographically encoded rights management control information.
In accordance with still another feature provided by the invention, steganography is used to encode an information signal with rights management control information in the form of one or more protected organizational structures having association with electronic controls. The electronic controls may, for example, define permitted and/or required operation(s) on content, and consequences of performing and/or failing to perform such operations. The organizational structure(s) may identify, implicitly or explicitly, the content the electronic controls apply to. The organizational structure(s) may also define the extent of the content, and semantics of the content.
The type, amount and characteristics of the steganographically encoded rights management control information are flexible and programmable--providing a rich, diverse mechanism for accommodating a wide variety of rights management schemes. The control information can be used to securely enforce straightforward secure rights management consequences such as "copy/no copy/one copy" type controls--but are by no means limited to such models. To the contrary, the present invention can be used to enable and enforce much richer, more complex rights management models--including for example those involving usage auditing, automatic electronic payment, and the use of additional electronic network connections. Moreover, the rights management control arrangements provided by the present invention are infinitely extensible and scaleable--fully accommodating future models as they are commercially deployed while preserving full compatibility with different (and possibly more limited) rights management models deployed during earlier stages.
The organizational structure(s) may be steganographically encoded in such a way that they are protected for purposes of secrecy and/or integrity. The employed steganographic techniques may provide some degree of secrecy protection--or other security techniques (e.g., digital encryption, digital seals, etc.) may be used to provide a desired or requisite degree of security and/or integrity protection for the steganographically encoded information.
In one example, the organizational structure(s) may comprise digital electronic containers that securely contain corresponding digital electronic control information. Such containers may, for example, use cryptographic techniques. In other examples, the organizational structure(s) may define associations with other electronic control information. The other electronic control information may be delivered independently over the same or different communications path used to deliver the organizational structure(s).
In one example, the steganographic techniques employed may involve applying the organizational structure information in the form of high frequency "noise" to an analog information signal. Spectral transforms may be used to apply and recover such steganographically-encoded high frequency "noise." Since the high frequency noise components of the information signal may be essentially random, adding a pseudo-random steganographically encoded control signal component may introduce substantially no discernible information signal degradation, and may be difficult to strip out once introduced (at least without additional knowledge of how the signal was incorporated, which may include a shared secret).
In accordance with another aspect provided by the invention, a steganographic encoding process analyzes an information signal to determine how much excess bandwidth is available for steganographic encoding. The steganographic encoding process may use variable data rate encoding to apply more control information to parts of an information signal that use much less than all of the available communications channel bandwidth, and to apply less control information to parts of an information signal that use nearly all of the available communications channel bandwidth.
In accordance with still another aspect provided by the invention, multiple organizational structures may be steganographically encoded within a given information signal. The multiple organizational structures may apply to different corresponding portions of the information signal, and/or the multiple organizational structures may be repetitions or copies of one another to ensure that an electronic appliance has "late entry" and/or error correcting capability and/or can rapidly locate a pertinent organizational structure(s) starting from any arbitrary portion of the information signal stream.
In accordance with yet another aspect provided by this invention, an organizational structure may be steganographically encoded within a particular portion of a content-carrying information signal to which the organizational structure applies--thereby establishing an implicit correspondence between the organizational structure and the identification and/or extent and/or semantics of the information content to which the organizational structure applies. The correspondence may, for example, include explicit components (e.g., internally stated start/end points), with the storage or other physical association determined by convenience (i.e., it may make sense to put the organizational structure close to where it is used, in order to avoid seeking around storage media to find it).
In accordance with yet another aspect provided by this invention, pointers can be steganographically encoded into parts of an information signal stream that has little excess available bandwidth. Such pointers may be used, for example, to direct an electronic appliance to portions of the information signal stream having more available bandwidth for steganographic encoding. Such pointers may provide improved steganographic decode access time--especially, for example, in applications in which the information signal stream is stored or otherwise available on a random access basis.